ZipcodeZoo.com

Trapa natans

(Water Chestnut, Water Chestnut Trapa Natans, Water Nut)

Overview:

Conservation Status

[ Back to top ]

Population Analysis

  • For the 835,580 species in the Class Magnoliopsida (Dicotyledons), we average 4.30 observations each in our database; for the Water Chestnut Trapa Natans, we have 407 observations. Compared to other species in this Class, this species is moderately common.
  • A two-sample t-test can be used to determine whether the trend in observations of the Water Chestnut Trapa Natans is the same as the trend in observations of Magnoliopsida. Is this species just as common, as a proportion of all observations, as it once was? The answer is no, changes in observation rate of this species significantly differ from changes in observation rate of its Class. (t=4.334, p<0.001)
  • How do observation rates of the Water Chestnut Trapa Natans differ from those of Magnoliopsida? To answer this, we examined the percentage of observerations for Magnoliopsida that were observations of the Water Chestnut Trapa Natans each year. We then correlated this percentage with observation year. If observations of the Water Chestnut Trapa Natans are becoming more common relative to other species of Magnoliopsida, the correlation should be positive, but if it is becoming less common, the correlation should be negative. In fact, the correlation is negative (r=-.18), with a negative slope (m = -.000), suggesting that the Water Chestnut Trapa Natans may be in decline relative to other species of Magnoliopsida. This correlation is statistically significant. (F = 36.82, p<.05)
  • The scatter chart to the right shows the percentage of all observations for Magnoliopsida each year that were observations of the Water Chestnut Trapa Natans.

Status

Invasive.

Nativity: Eurasia. • Date introducted to the U.S.: Mid 1800s. • Means of introduction: Ornamental. • Impact: Crowds out native species. • Management Plans: here.[1]

Taxonomy

[ Back to top ]
  • Domain: Eukaryota Whittaker & Margulis,1978 - eukaryotes

Notes:

Publishing author: Roxb. Publication: Hort. Bengal. 11; Fl. Ind. i. 428.

Name Status: Accepted Name. Latest taxonomic scrutiny: 15-Mar-2000

Place of publication: Sp. pl. 1:120. 1753

Name verified on 07-Nov-1985 by ARS Systematic Botanists. Last updated: 23-Aug-1994

Physical Description

[ Back to top ]

Family Trapaceae:

Herbs annual, aquatic, rooted or floating. Stem submerged, slender, unbranched, internodes elongate; adventitious roots developing from leaf scars, highly dissected, leaflike, photosynthetic. Leaves dimorphic; stipules deeply cleft; submerged leaves opposite, sessile, simple, linear, caducous; floating leaves crowded terminally into a rosette, petiolate; petiole inflated about the middle; leaf blade rhombic to deltoid, distal half of margin coarsely dentate. Flowers solitary in upper leaf axils, flowering at water surface, bisexual, 4-merous, actinomorphic. Floral tube (hypanthium) developed, partly epigynous. Sepals 4, valvate, persistent as hardened horns of fruit. Petals 4, white or lilac, deciduous. Stamens 4, antesepalous; anthers introrse, versatile. Ovary surrounded by a coronary disk, partly inferior, becoming inferior in fruit, 2-loculed; ovules anatropous, pendulous, 1 per locule, 1 ovule undeveloped after anthesis; placentation axile. Stigma capitate, deciduous. Fruit indehiscent, (0-) 2-4-horned, turbinate, cup-shaped, or elongate rhombic, exocarp succulent, ephemeral, endocarp stony, with a thin to prominent crest between and along horns, fruit topped by a dome-shaped or tetragonal to rounded crown, crown apex a pointed beak or tuft of hairs. Seed 1; cotyledons unequal, 1 large, starchy, retained in fruit, 1 small, scalelike, germinating from fruit apex, through pore of stylar canal; endosperm absent.

One genus and two species: subtropical and temperate regions of Africa, Asia, and Europe; introduced in Australia and North America; two species in China.

Trapa is allied morphologically to the Lythraceae by the partly inferior position of the ovary together with a host of other features, including basically opposite, simple leaves, development of the floral tube which persists in fruit, valvate sepals, 4-merous flowers, introrse and versatile anthers, axile placentation, and seeds without endosperm. Trapa is sufficiently similar to the Lythraceae and Onagraceae to have been considered for membership within either family or, as has been done here, as a closely related family. Molecular evidence suggests the closest relative is Sonneratia (Lythraceae) .[2]

Genus Trapa:

Morphological characters and geographic distribution are the same as those of the family.

Numerous species and infraspecific taxa have been proposed based on variations in size and ornamentation of the fruit. However, these variations overlap to such an extent that a more discrete definition of taxa is not supported here.

Plants are regionally cultivated for their fruit, which contain abundant starch and are consumed both raw and cooked. The seeds are ground into a flour used for medicine and making starch and wine. The fruit and fresh plants can be used for pig feed.[3]

Species Trapa natans:

Stem 2.5-6 mm in diam. Petiole (2-) 5-18 cm, stout, ± swollen distally, pubescent; leaf blade glossy and dark green adaxially, greenish purple abaxially, often with colored spots between veins, deltoid-rhombic to oblate-rhombic, 4-6 × 4-8 cm, abaxially pubescent, adaxially glabrous, base broadly cuneate, margin irregularly dentate distally. Petals white, 7-10 mm. Fruit turbinate to shortly rhombic, 1.8-3 × 2-4.5 × 1-2.8 cm, (0-) 2-4-horned, crest a prominent bulge to a thin rib, crown tetragonal to rounded, or dome-shaped, rarely crownless, 1-8(-11) mm, beak conic or a tuft of hairs; horns horizontal, ascending, or recurved, flat-triangular or broadly conic, 2-3.5 cm, apex barbellate or cultivated without barbs. Fl. May-Oct, fr. Jul-Nov. 2n = 44*, 46*, 48*, 76*, 90*, ?96. [source]

In FRPS (53(2) : 7, 9. 2000), the names Trapa macropoda Miki, T. mammillifera Miki, and T. octotuberculata Miki, all of which are based on fossil types, were misapplied to plants of T. natans. [source]

Habit: Forb/herb

Flowers: Flower Color: near white, white

Images:

Distribution

[ Back to top ]

Range and Population

Bangladesh. North America

Native: Jiangxi, Sichuan, Yunnan.

Habitat

[ Back to top ]

Slow-moving rivers, lakes, swamps, ponds, also widely cultivated in China; near sea level to 2700 m[4].

Biome

National Biological Information Infrastructure (NBII)

Reproduction

[ Back to top ]

Duration: Perennial

Growth

[ Back to top ]

Culture: Space 6-9" apart.

Sunlight: Sun Exposure: Full Sun.

Similar Species

[ Back to top ]

Members of the genus Trapa:

There are approximately 165 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them: T. brevicarpa calosa · T. longicarpa valida · T. acicularis · T. acornis · T. alatyrica · T. algeriensis · T. americana · T. amurensis · T. angulata · T. angusticerata · T. annosa · T. annosa f. bicornis · T. annosa f. erecticornis · T. annosa f. pseudomuzzanensis · T. anteformata · T. antennifera · T. araborum · T. arcuata · T. assamica · T. astrachanica · T. astrachanica var. caspica · T. austroafricana · T. bicornis (Horn Nut) · T. bicornis var. acornis · T. bicornis var. bispinosa · T. bicornis var. coreanus · T. bicornis var. quadrispinosa · T. bicornis var. taiwanensis · T. borealis · T. borysthenica · T. brevicarpa · T. brevicarpa f. effigia · T. brevicarpa f. perexcelsa · T. brevicarpa f. quadrata · T. brevicarpa rubida · T. brevicarpa subsp. calosa · T. brevicarpa subsp. rubida · T. brevicarpa var. delicata · T. brevicarpa var. mirabila · T. carinthiaca · T. caspica · T. castanea · T. caucasica · T. chinensis · T. cochinchinensis · T. colchica · T. congolensis · T. conocarpa · T. conocarpa var. pyramidalis · T. conocarpa var. suecica · T. cruciata · T. danubialis · T. dolichocarpa · T. europaea · T. europaea var. clipeata · T. europaea var. egregia · T. europaea var. macrocarpa · T. europaea var. vulgata · T. excelsa · T. fastigiata · T. flerovii · T. grozdovii · T. hankensis · T. heerii · T. hungarica · T. hyrcana · T. incisa · T. insperata · T. irtyshensis · T. jankovicii · T. japonica · T. japonica var. jeholensis · T. japonica var. longicollum · T. japonica var. magnicorona · T. japonica var. tuberculifera · T. jeholensis · T. kasachstanica · T. kashmirensis · T. kazakorum · T. komarovii · T. korshinskyi · T. kozhevnikoviorum · T. krauselii · T. laevis · T. litwinowii · T. litwinowii var. chihuensis · T. longicarpa · T. longicarpa f. brevicola · T. longicarpa f. columnifera · T. longicarpa f. depressa · T. longicarpa f. elata · T. longicarpa f. elongata · T. longicarpa f. falcata · T. longicarpa f. producticarpa · T. longicarpa f. subcoronata · T. longicarpa f. turgida · T. longicarpa perlongicornis · T. longicarpa subsp. perlongicornis · T. longicarpa subsp. valida · T. longicarpa subvar. miniata

Bibliography

[ Back to top ]

More Info

[ Back to top ]

Notes

[ Back to top ]

Contributors:

  • "Trapa natans". in Flora of China Vol. 13 Page 290, 291. Published by Missouri Botanical Garden Press. Online at EFloras.org.
  • Bisby, F.A., Y.R. Roskov, M.A. Ruggiero, T.M. Orrell, L.E. Paglinawan, P.W. Brewer, N. Bailly, J. van Hertum, eds (2007). Species 2000 & ITIS Catalogue of Life: 2007 Annual Checklist. Species 2000: Reading, U.K.
  • Brands, S.J. (comp.) 1989-2007. Systema Naturae 2000. The Taxonomicon. Universal Taxonomic Services, Amsterdam, The Netherlands. Accessed March 24, 2007.
  • Global Biodiversity Information Facility. Accessed November 15, 2007. http://www.gbif.org Mediated distribution data from 17 providers.
  • National Invasive Species Information Center, National Agricultural Library, United States Department of Agriculture. Web Site. Accessed May 3, 2008.
  • The International Plant Names Index. Accessed Jan 19, 2007.
  • USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. URL (April 24, 2008)

Data Sources:

Accessed through GBIF Data Portal November 15, 2007:

Identifiers:

Footnotes:

  1. National Invasive Species Information Center, National Agricultural Library, United States Department of Agriculture. Web Site. Accessed May 3, 2008.
  2. Jiarui Chen, Bingyang Ding & Michele Funston "Trapaceae". in Flora of China Vol. 13 Page 274, 290. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org.
  3. "Trapa". in Flora of China Vol. 13 Page 274, 290. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org.
  4. "Trapa natans". in Flora of China Vol. 13 Page 290, 291. Missouri Botanical Garden Press. Online at EFloras.org.

Keep Exploring...

[ Back to top ]
Loading...
Loading...

What is this? Click to find out...

Loading...
Loading...
Last Revised: May 05, 2008